code: def test_one_point(self, atol):
      X = gs.expand_dims(
          self.data_generator.random_point(n_points=1), axis=0
      )
  
      mean = self.estimator.fit(X).estimate_
      self.assertAllClose(mean, X[0], atol)
  
file_path: geomstats/geomstats/test_cases/learning/_base.py
imports: import pytest
  import geomstats.backend
  from geomstats.test.random import RandomDataGenerator
  from geomstats.test.test_case import TestCase
  from geomstats.vectorization import repeat_point
label_desc: Use image node_id 2 for calling the MeanEstimatorMixinsTestCase obj's underlying member method code with example usage: obj.test_one_point(atol) without return types